Nothing is known of Galatea Merrythought's past, although it is likely that she attended [[Hogwarts School of Witchcraft and Wizardry]] and would've purchased her [[wand]] from [[Garrick Ollivander]]'s [[Ollivanders Wand Shop|Wand Shop]] at [[Diagon Alley]] at the age of eleven. She would've graduated at the age of seventeen and it is likely that she had good [[Defence Against the Dark Arts]] marks, and possibly a [[Nastily Exhausting Wizarding Test|N.E.W.T.]]

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Nothing is known of Galatea Merrythought's past, although it is likely that she attended [[Hogwarts School of Witchcraft and Wizardry]] and would have purchased her [[wand]] from [[Garrick Ollivander]]'s [[Ollivanders Wand Shop|Wand Shop]] at [[Diagon Alley]] at the age of eleven. She would have graduated at the age of seventeen and it is likely that she had good [[Defence Against the Dark Arts]] marks, and possibly a [[Nastily Exhausting Wizarding Test|N.E.W.T.]]

Professor Galatea Merrythought was a witch and Professor of Defence Against the Dark Arts from 1895 to 1945, holding the position for fifty years. She worked alongside Albus Dumbledore and Horace Slughorn, her former students, but eventually retired. Some considerable time after her retirement, Tom Riddle, another one of her pupils, was refused the chance to take her place, and so jinxed the post so no wizard could hold the occupation for longer than a year. Her ultimate fate remains unknown, although, if she is still alive, she would be over 130 years old.

The Chamber of Secrets and retirement

Many years later, when Professor Dippet was Headmaster, Galatea became the teacher of a brilliant student named Tom Riddle. Her fellow colleagues, and possibly Galatea herself, had been impressed by Riddle's skills and determination, and taught him all they knew. During her fifth year of teaching Riddle, the Chamber of Secrets was opened and many of her students were petrified. Eventually, a third-year named Rubeus Hagrid was accused of releasing Slytherin's monster from the Chamber and he was expelled. It was during this year that Galatea decided to retire, whether it was because of these events or not, and she left the school following year.

Etymology

The surname Merrythought could imply that she was adept at conjuring the Patronus. However, due to the fact that she taught Defence Against the Dark Arts at Hogwarts for fifty years, it could also be that her anti-Dark Arts knowledge was extensive to the degree that she could perform the Patronus charm, which several fully-qualified wizards often have trouble with.

Her given name Galatea may well be derived from Greek mythology. In Ancient Greek, the root forms would be gala(-ktos), meaning "milk", and -tea, "white". There are three notable women in Greek mythology named Galatea: First Galatea of Sicily, one of the fifty daughters of Nereus and Doris known as the Nereids, was courted by both Polyphemus and Acis. Second, Galatea of Cyprus was the wife of King Pygmalion. Pygmalion was famous for having created a statue of Aphrodite, the Goddess of Love, that the goddess brought to life at his request. After receiving the gift of life, Galatea married the king. Last, Galatea was the name of the wife of King Lamprus. Galatea prayed to the Greek goddess Leto to transform her daughter into a son so she would not have to sacrifice her according to the command of her husband. Leto granted Galatea's request.

Behind the scenes

"And I'll want Professor Merrythought's old office! Not the water closet I had before!"

In the sixth movie, after finally agreeing to come back and teach at Hogwarts, Horace Slughorn demands that when he comes back to Hogwarts, he is given Merrythought's old office; however, this does not coincide with the book, in which he merely asks for a pay raise.